DESCRIPTION: This proposal requests funding to develop and test a system by which cryopreserved human sperm can be thawed without damage. The P.I. points out that for most samples of cryopreserved sperm glycerol is used as the cryoprotectant. Thawing results in more than 50 percent of the sperm being damaged due to change in the osmotic environment which distends and damages or ruptures the plasma membrane. If the glycerol concentration is reduced slowly this minimizes damage but is impractical in the clinical setting. Alternative cryoprotectants which reduce damage such as ethylene glycol must be removed prior to insemination to prevent tissue irritation. A simple automated system to remove cryoprotectant from thawed human sperm at a non-damaging but rapid rate would improve success with sperm cryopreserved using glycerol. This is a phase 1 project which has three specific aims: 1) fabricate a prototype removal device to automatically and rapidly remove cryoprotectant from human sperm without a change in sperm concentration; 2) to evaluate capability of the prototype RCRD to remove cryoprotectant from sperm contained in a CryoCell container at a rate which is fast and non-damaging using glycerol as a test cryoprotectant; and 3) using thawed human sperm to compare quality of sperm deglycerolated and returned at 290 mOsm buffer using BioPore technology with that of sperm returned to that concentration buffer by conventional abrupt dilution or by slow step-wise dilution. It is suggested that fertility would be improved by use of this technology minimizing damage to human sperm. This is important for men having their sperm cryopreserved for therapy or surgery that is likely to impair testicular function. It will also benefit women requiring insemination with donor semen. It is estimated that by the year 2002 demands in these areas would be greater than 1 million and greater than 0.4 million doses respectively resulting in adequate sales potential for a system meeting project goals.